Clinical feasibility of low energy internal atrial cardioversion with a three-electrode configuration in patients with unsuccessful conventional configurations.

Low energy internal cardioversion is a safe and highly effective method for atrial fibrillation termination. We will describe 6 patients in whom the conventional 2-electrode systems with the defibrillation leads positioned in the right atrium and in the coronary sinus or left pulmonary artery failed to terminate the arrhythmia despite the use of maximal available energies. A 3-electrode configuration including right atrium, coronary sinus and left pulmonary artery was used in order to encompass as much atrial mass as possible between the cathode and the anode. The atrial fibrillation was successfully interrupted in 4 out of 6 patients. The creation of a 3-electrode configuration may be a further technical expedient in order to increase the success rate of internal cardioversion when usual manoeuvres like lead repositioning, reversion of polarity, or addition of antiarrhythmic drugs are ineffective.

a 49-year-old woman with dyspnoea, palpitations and syncope.

Pulmonary hypertension is rarely described in association with Sjögren's syndrome. The authors report the case of a patient in which pulmonary hypertension was the inaugural clinical manifestation of primary Sjögren's syndrome. Clinical assessment, differential diagnosis, etiopathological implications, and therapeutic approach are discussed.

Long-term reliability of single lead atrial synchronous pacing systems using closely spaced atrial dipoles: five-year experience.

To assess the long-term capability of single atrioventricular (AV) lead VDD pacing systems using close atrial dipoles to assure reliable atrial guided pacing, the safety and efficacy of 86 VDD units implanted in 73 patients at a single center since November 1988 was reviewed. All patients suffered from advanced AV block with normal sinoatrial function. Sixty five patients received a LEM/CCS Twinal 30/30S system, four patients received a Vitatron-Saphir system, and four patients received a Medtronic Thera VDR 8348 system. All patients underwent provocative tests in search of myopotential interference, and Holter recordings; in a group of patients who underwent pacemaker replacement a comparison was made between implant and replacement measurements. The mean follow-up duration was 27.3 months. A high percentage of successfully VDD paced patients and a low incidence of pacemaker malfunction, regularly solved by pacemaker reprogramming, was reported. Atrial signal amplitudes comparable to those measured at implant were found at replacement in all patients. These data support the long-term reliability of single AV lead VDD pacing systems with closely spaced atrial dipoles, as well as stable atrial sensing by floating bipolar atrial electrodes and effective atrial synchronous ventricular pacing over time.

AV delay optimization and management of DDD paced patients with dilated cardiomyopathy.

Ten DDD paced patients, suffering from dilated cardiomyopathy in the NYHA functional classes III or IV were studied by means of Doppler echocardiography at different programmed values of atrioventricular (AV) delay (200, 150, 120, 100, and 80 msec). The following variables were evaluated: LV diameter, ejection fraction, mitral and aortic flow velocity integrals, and stroke volume. During VDD pacing, a resting AV delay associated with the best diastolic filling and systolic function was identified and programmed individually. Shortening of the AV delay to about 100 msec was associated with a gradual and progressive improvement. Further decrease caused an impairment of systolic function. The patients were clinically and hemodynamically reevaluated after 2 months of follow-up. A reduction of NYHA class and an improvement of LV function were consistently found. The reported data suggest that programming of an optimal AV delay may improve myocardial function in DDD paced patients with congestive heart failure. This result may be the consequence of an optimization of left ventricular filling and a better use of the Frank-Starling law.

Direct and autonomically mediated effects of oral quinidine on RR/QT relation after an abrupt increase in heart rate.

OBJECTIVES: This study evaluates the direct and autonomically mediated effects of oral quinidine on ventricular repolarization in humans. BACKGROUND: Interactions between quinidine-related vagolytic properties and autonomic modulation on ventricular repolarization are unknown. The relative role of the two components, if present, might improve our understanding of the therapeutic and proarrhythmic mechanisms of quinidine on the ventricular tissue. METHODS: Rate-related changes in the QT interval were investigated after an abrupt increase in heart rate in 15 patients during atrial pacing. In the control study, the QT interval was measured at six paced cycle lengths (600, 540, 500, 460, 430 and 400 ms) both in the basal state and after autonomic blockade (intravenous propranolol, 0.2 mg/kg, and intravenous atropine, 0.04 mg/kg); oral quinidine was then administered at a daily dosage of 1,200 mg for 3 to 4 days, after which the QT duration was reassessed using the same method in a second study. RESULTS: During the control study, the mean slope of the regression curve estimating the correlation between pacing cycle length and QT duration was significantly lower after autonomic blockade (0.14 +/- 0.05) than in the basal state (0.27 +/- 0.10, p < 0.05). Quinidine exhibited a prominent but opposite effect on the mean slope of the regression curves in basal conditions (from 0.27 +/- 0.10 to 0.20 +/- 0.07, p < 0.05) and after withdrawal of autonomic modulation (from 0.14 +/- 0.05 to 0.19 +/- 0.05, p < 0.05), thus annulling the differences observed between the two states in the control study. CONCLUSIONS: A quinidine-induced increase in QT duration as cycle length is prolonged is consistent with a reverse use dependence effect on ventricular repolarization. This effect is not evident in the basal state owing to interaction of quinidine-related vagolytic effect with the autonomic tone. Reverse use dependence and vagolytic activity on ventricular tissue indicate two potentially undesirable effects that could play a role in the lack of efficacy or proarrhythmic effect of quinidine.

Italian multicenter study on a single lead VDD pacing system using a narrow atrial dipole spacing.

Since November 1988, 514 patients with advanced atrioventricular (AV) block and normal sinoatrial function have received the single lead VDD pacing system Twinal 30 Lem/CCS in 30 Italian centers. At implantation, particular attention was paid to the correct positioning of the atrial dipole in the mid- to mid-high right atrium and to the atrial electrogram characteristics. The follow-up included a chest X ray, to be performed before discharge of the patient from the hospital, telemetric evaluations of the endoatrial potential, provocative tests for interferences by myopotentials, 24-hour ambulatory EGG recordings, and where possible, exercise stress tests. The mean follow-up duration was 15.2 months, ranging from 1 to 42 months. A very low percentage of chronic atrial fibrillation, loss of atrial sensing, and system replacement was reported, most of the patients (93.5%) being paced in VDD mode. All investigations indicated an excellent overall system performance, stable AV synchrony, and infrequent myopotential interference, and a low complication rate throughout the follow-up period.

AV delay and exercise stress tests: behavior in normal subjects.

In normal subjects the atrioventricular (AV) conduction is accelerated during exertion. The relationship between heart rate and AV delay is usually described as "linear". Looking at the increasing importance given to an appropriate AV synchrony in permanent dual chamber and P synchronous pacing we present the results of an investigation performed to study the correlation between AV conduction time and heart rate under stress conditions, and disclose some new aspects of this matter, which will possibly be useful for a further improvement of pacemaker technology.

A new single lead VDD pacing system.

In 24 patients with advanced heart block and normal sinus node function, a new single lead VDD pacing system was implanted. At implantation, the endoatrial, bipolar electrogram was recorded in all patients. The lead position was checked by means of chest X-ray. At discharge and after 1, 3, and 6 months, testing for myopotential inhibition, telemetric evaluation of the endoatrial potential, and Holter recordings were made. After discharge, 18 patients performed two cardiopulmonary exercise tests at two different rate-matched AV intervals. All investigations showed good AV synchrony and a lack of interferences by myopotentials. The maximum rate-matched AV interval provided a significantly improved exercise capacity, which was more evident in patients with signs of myocardial failure.

Peripheral hemodynamic effects of ibopamine in patients with congestive heart failure. A placebo-controlled, double-blind study.

Under double-blind conditions, 150 mg of ibopamine (di-isobutyric ester of N-methyldopamine) or placebo were given orally to 11 patients with congestive heart failure; after 3 hours, 50 mg of sulpiride were administered intramuscularly. Peripheral hemodynamics were evaluated at the level of the forearm using strain-gauge plethysmography. Ibopamine increased arterial blood flow and venous capacity and decreased arterial peripheral resistance; these effects were counteracted by sulpiride. No significant changes were observed after placebo and sulpiride. These findings confirm the vasodilating effects of ibopamine on peripheral hemodynamics and its utility in patients for the treatment of congestive heart failure.

Bedside evaluation of sinus bradycardia: usefulness of atropine test in discriminating organic from autonomic involvement of sinus automaticity.

In 55 patients with persistent sinus bradycardia who underwent an electrophysiologic study of sinus node, both in the basal state and after autonomic blockade (propranolol, 0.2 mg/kg, and atropine, 0.04 mg/kg), an atropine test (0.02 mg/kg) was performed the following day. The 49 patients in whom sinus rate could be evaluated after atropine were subdivided into two groups--group I, 24 patients (age: 54 +/- 13 years) with normal intrinsic sinus automaticity (normal intrinsic heart rate and intrinsic corrected sinus node recovery time) and group II, 25 patients (age: 62 +/- 9 years) with abnormal intrinsic sinus automaticity. In group I, atropine increased sinus rate from 53.7 +/- 4 to 87.9 +/- 17 bpm (delta %: 65.5 +/- 33) and in group II from 51.6 +/- 5 to 73.9 +/- 14 bpm (delta %: 43.1 +/- 26). The discriminant threshold of sinus rate after atropine and its percent increase, obtained by discriminant analysis, was 80 bpm and +52%, respectively, with a misleading classification of 32% and 36%, respectively. The overall predictive accuracy of sinus rate after atropine was higher than the percent change in sinus rate (73% and 65%, respectively). These data evidence that the atropine test is not very helpful in discriminating between an organic and an autonomic involvement of sinus automaticity in patients with sinus bradycardia.

Effects of ibopamine on peripheral hemodynamics: a strain gauge plethysmographic study in patients with congestive heart failure.

Peripheral hemodynamics were studied using strain gauge plethysmography in patients with congestive heart failure after administration of ibopamine (SB-7505), the orally active 3,4-diisobutyryl ester of N-methyldopamine, a dopaminergic agonist, and of sulpiride, a specific dopaminergic antagonist. 50 mg of sulpiride were administered parenterally in 12 patients 3 h after a single oral dose of 150 mg of ibopamine. Ibopamine increased significantly resting arterial blood flow and venous capacity and decreased peripheral resistance. Sulpiride was found to significantly counteract the activity of ibopamine.

Atrial septal aneurysm: echopolycardiographic study.

Atrial septal aneurysm (ASA) with diagnosis during life is a rarely reported anomaly, especially when not associated with other congenital or acquired valvular cardiopathies. Among 4,000 routine echocardiograms, 23 cases of ASA were found (8 men and 14 women, aged 19 to 79 years). Three patients had coronary artery disease, 2 had dilated cardiomyopathy, 2 had systemic hypertension, 11 had mitral valve prolapse and 5 had no other identifiable cardiovascular diseases. Echocardiography revealed various motion patterns of ASA. No phonomechanocardiographic findings were related to the presence of ASA, and no correlation between echographic and phonocardiographic findings was found.

Phonometric study of the second heart sound in normal man.

The fast Fourier transform (FFT) was employed to analyze the frequency spectra of the second heart sound in 19 healthy subjects. The data obtained show that the second heart sound is mainly composed of low-frequency vibrations, and that the frequency vs. amplitude spectra for the various filters do not exceed 150 Hz. The different spectra obtained can represent a useful reference to compare with pathological acoustical findings.

Effect of ibopamine on peripheral haemodynamics.

Peripheral haemodynamics was studied in healthy volunteers by strain gauge plethysmography after administration of ibopamine (IB), diisobutyric ester of N-methyl-dopamine, an orally active dopaminergic agonist. Seven subjects received a single oral dose of ibopamine of 150 mg and 6 received a daily dose of 150 mg (50 mg t.i.d.) for 5 consecutive days. Arterial resting blood flow and venous capacity increased and peripheral resistance decreased significantly. Six further subjects were then studied; 3 h after an oral dose of ibopamine 150 mg, the parenteral administration of Sulpiride 50 mg, a specific vascular dopaminergic antagonist, was found significantly to counteract its peripheral activity. Heart rate and arterial blood pressure were never affected and tolerability was good.

Two-dimensional echocardiography in post traumatic tricuspid incompetence.

Four patients with post traumatic tricuspid incompetence underwent complete two-dimensional echocardiographic study. Systolic intra-atrial protrusion of the anterior tricuspid leaflet beyond the valvular ring, with total loss of coaptation with the other leaflets, was documented in all patients. These abnormalities were not evident in all transducer locations suggesting the possibility of false negative echocardiograms. An echocardiogram showing a marked systolic excursion of a tricuspid leaflet into the right atrium beyond the level of the tricuspid ring together with the total loss of coaptation does not necessarily mean the rupture of the subvalvular apparatus.